Vosk is a leader of a temporal cold war faction from the 29th century. His species is never named.
Silik is killed by a Nazi soldier. John Fleck is seen without Suliban make-up when Silik is in human disguise.

"Home"

Episode Number

79

Trip and T'Les watch T'Pol well on her wedding day

Production Number

079

Season

4

Stardate

Original Airdate

10/22/2004

Story

Teleplay

Michael Sussman

Director

Allan Kroeker

Synopsis

Once the Enterprise finally returns to Earth, the weary crewmen face repercussions of their journeys, both positive and negative.

While the crew takes rest and relaxation, Enterprise goes through a repair and refit.
Since the Xindi attack, there has been a rise in xenophobia, which Phlox experiences in a local bar. This theme will be explored further later in the season (see "Demons").
This is the first appearance of T'Pol's mother, T'Les, who was forced to retire from the Science Academy because of T'Pol's role in "The Andorian Incident".
Trip travels to Vulcan with T'Pol, where she follows through with her pre-arranged marriage to Koss (see "Breaking the Ice") after he offers to help reinstate T'Les. T'Les knows that Trip is in love with T'Pol and she urges him to tell her, but he is unable to.
T'Pol has been offered a commission in Starfleet.
Erika Hernandez has been selected to command the second NX-class starship, the Columbia NX-02. She and Archer apparently have a romantic past.
Trip states that Vulcan is 16 light-years from Earth. It is generally given that Vulcan orbits the star 40 Eridani, which is approximately 16 light years from Earth.

"Borderland"

Episode Number

80

Dr. Arik Soong boards Enterprise

Production Number

080

Season

4

Stardate

17-May-2154

Original Airdate

10/29/2004

Story

Teleplay

Ken LaZebnik

Director

David Livingston

Synopsis

When genetic supermen left over from the Eugenics Wars hijack a Klingon ship, Archer must rely on their creator, the criminal Dr. Arik Soong, to help hunt them down. Upon reaching the volatile Borderland, T'Pol and eight other crewmen are kidnapped by Orion slave traders.

This episode is part 1 of a 3-part arc featuring Soong and the augmented humans.
The Borderland is a volatile area of space between the Klingon Empire and the Orion Syndicate.
This is T'Pol's first official day as a Starfleet officer; She has been given the rank of Commander. For some reason she does not wear a Starfleet uniform, but a cross between her 3rd season jumpsuit and the Starfleet uniform, including the Enterprise patch and the three rank pips.
Arik Soong is a distant relative of Noonien Soong, creator of the android Data. (Brent Spiner is obviously best known for his role as Data on Star Trek: The Next Generation.)
J.G. Hertzler also played Klingon General/Chancellor Martok on Deep Space Nine.

"Cold Station 12"

Episode Number

81

Dr. Soong and his Augments take control of CS12

Production Number

081

Season

4

Stardate

Original Airdate

11/5/2004

Story

Teleplay

Michael Bryant

Director

Mike Vejar

Synopsis

Arik Soong leads his band of Augments to a medical facility where hundreds of genetically enhanced embryos are still stored, intending to retrieve them and bring them to life.

Part 2 of 3.
Cold Station 12 is a Starfleet/Denobulan medical research facility which also serves as a storage facility for hazardous pathogens in addition to the 1800 augment embryos.
This the first of two appearances of Phlox' friend Dr. Lucas, the recipient of his letters throughout the series. Lucas was recently transferred to Cold Station 12 as senior medical director.

"The Augments"

Episode Number

82

Dr. Soong helps Archer find the Augments

Production Number

082

Season

4

Stardate

27-May-2154

Original Airdate

11/12/2004

Story

Teleplay

Michael Sussman

Director

LeVar Burton

Synopsis

In defiance of their "father," Arik Soong's Augments devise a heinous plot against the Klingons which will surely lead to interstellar war.

Part 1 of 3.
Admiral Forrest dies saving Ambassador Soval. 43 people died in total (12 Vulcans and 31 Humans).
The evidence points to the Syrannites, a small group of Vulcans who follow a "corrupted" form of Surak's teachings. DNA from a known Syrannite named T'Pau is found, but Phlox discovers that it was planted.
Soval becomes an ally to the crew, and begins working with the crew to discover what happened. He mind melds with the comatose guard and discovers that Stel planted the bomb in the Embassy.
Koss delivers an IDIC pendant to T'Pol, and informs her that her mother T'Les is a Syrannite and that she has disappeared. The pendant gives them directions to find her.
V'Las is the Administrator of the Vulcan High Command.

"Awakening"

Episode Number

84

T'Pau tries to extract Surak's katra from Archer

Production Number

084

Season

4

Stardate

Original Airdate

11/26/2004

Story

Teleplay

André Bormanis

Director

Roxann Dawson

Synopsis

Archer and T'Pol encounter the Syrrannites, a radical group hiding in the Vulcan desert, while the Enterprise crew contends with Vulcan power ploys.

Part 2 of 3.
The High Command dismisses Soval for his actions in the previous episode.
The Syrannites follow the true teaches of Surok, the founder of Vulcan society. Arev, who died in the previous episode, was actually Syran, the leader of the Syrannites. Syran carried the katra of Surok. Before he died, he transferred the katra to Archer.
T'Pol's mother T'Les dies in the attacks on the Syrrannites.
Dr. Phlox does not appear in this episode.

"Kir'Shara"

Episode Number

85

T'Pau cures T'Pol of her Pa'nar Syndrome

Production Number

085

Season

4

Stardate

Original Airdate

12/3/2004

Story

Teleplay

Michael Sussman

Director

David Livingston

Synopsis

Archer, T'Pol and T'Pau attempt to bring the Kir'Shara -- an artifact believed to contain Surak's original writings -- to the Vulcan capital, as the Enterprise gets involved in a Vulcan-Andorian military clash.

Part 3 of 3.
V'Las has convinced the Vulcan High Command that Andoria has Xindi technology and uses this fear to launch an invasion of Andoria. He is relieved of his duties for treason. This episode begins the turning point in Vulcan history when Vulcans begin their journey from the devious Vulcans of the Star Trek: Enterprise era to the species seen in the Original Series era and beyond.
T'Pau melds with T'Pol and cures her Pa'nar Syndrome (diagnosed in "Stigma"). According to T'Pau, it is caused by inexperienced melders and can be cured by a meld with an experienced melder. The Vulcan High Command created the stigma to discredit the Syrannites among the Vulcan people.
The final scene shows V'Las meeting with a Romulan, who denies him an escape and leaving re-unification for another time (see TNG two-part episode "Unification").

"Daedalus"

Episode Number

86

Archer is reunited with old friend Emory Erickson

Production Number

086

Season

4

Stardate

Original Airdate

1/7/2005

Story

Teleplay

Ken LaZebnik & Michael Bryant

Director

David Straiton

Synopsis

The crew welcomes aboard Emory Erickson, the inventor of the transporter device, set to conduct a series of experiments to test a radical upgrade to the technology. However, once Enterprise reaches the test site, Archer realizes that his old family friend has lied and is using the ship to search for his son, lost years before in a transporter mishap.

Emory Erickson was a friend of Archer's father; he is like a second father to Archer, who was a friend of Quinn's.
They locate Quinn, but he dies soon after he is beamed aboard Enterprise.
T'Pol begins studying the Kir'Shara, which is having a profound effect on all of Vulcan. Phlox verifies that her Pa'nar Syndrome is cured, and notes that others on Vulcan are coming forward to be cured as well.
Ensign Burrows dies when Quinn's energy field touches him.

"Observer Effect"

Episode Number

87

Hoshi 'comes back to life' to discuss the humans

Production Number

087

Season

4

Stardate

Original Airdate

1/14/2005

Story

Teleplay

Judith Reeves-Stevens & Garfield Reeves-Stevens

Director

Mike Vejar

Synopsis

After Hoshi and Trip contract a deadly virus while exploring a planet, two ghostly aliens possess the bodies of various Enterprise crew members to observe humanity's reaction to imminent tragedy. As the aliens secretly jump bodies to observe, Phlox strives to cure the stricken pair, but with his efforts failing, Archer must make a difficult decision in order to shield the rest of the crew from this growing biohazard.

Guest Cast

Notes

The non-corporeal aliens are the Organians, who first appeared in the Original Series episode "Errand of Mercy".

"Babel One"

Episode Number

88

The Enterprise crew welcomes the Tellarites

Production Number

088

Season

4

Stardate

12-Nov-2154

Original Airdate

1/28/2005

Story

Teleplay

Mike Sussman & André Bormanis

Director

David Straiton

Synopsis

Ordered to transport a delegation of argumentative Tellarites to a peace conference with the blue-skinned Andorians, Archer and the crew find themselves drawn into a confusing, dangerous situation when a secret Romulan vessel begins attacking ships on all sides, including Enterprise.

Part 1 of 3.
T'Pol receives a communication from Koss: their marriage is officially disolved.

"United"

Episode Number

89

The Tellarites and Andorians call a truce

Production Number

089

Season

4

Stardate

Original Airdate

2/4/2005

Story

Manny Coto

Teleplay

Judith Reeves-Stevens & Garfield Reeves-Stevens

Director

David Livingston

Synopsis

Trapped aboard a mysterious drone ship that's been terrorizing the region, Trip and Malcolm work to outwit the Romulans, who are piloting the vessel via remote control, in order to save their own lives and stop the feuding Andorians and Tellarites from going to war.

Part 2 of 3.
This episode sets up the beginnings of the forming of the United Federation of Planets, whose five charter members are the planets Earth, Vulcan, Andoria, Tellar, and the human colony Alpha Centauri.
Shran's mate, Talas, dies from her injuries after Naarg shot her in "Babel One".
During their duel, Archer cuts off one of Shran's antennae. According for Phlox, it will grow back naturally in 9 months, half that with treatment.
The remote pilot appears to be Andorian….
UPN announced this week that Season 4 will be the last season as it has cancelled Star Trek: Enterprise.

"The Aenar"

Episode Number

90

Jhamel agrees to use the telepresence device

Production Number

090

Season

4

Stardate

Original Airdate

2/11/2005

Story

Manny Coto

Teleplay

André Bormanis

Director

Mike Vejar

Synopsis

Archer visits Shran's icy homeworld to find an Andorian subspecies called the Aenar, to determine their connection to the marauder destroying ships in the region.

Part 3 of 3.
Trip's feelings for T'Pol seem to be overwhelming him. In the end, Trip requests a transfer to the Columbia. Archer agrees.
This is the first visit to the icy world of Andoria, a small planet which orbits a large, ringed gas giant. Andorian cities are built underground to take advantage of geo-thermal energy. During a "heat-wave," the surface temperature may be above freezing for several weeks. When Archer and Shran beam down, it is 28 degrees below 0 -- the middle of summer.
The Aenar (pronounced "EE-nar") are an Andorian subspecies. Very few Andorians have seen an Aenar. They are blind, ice-dwelling, non-violent isolationists who live in the northern wastes. They have pale, white skin, but are otherwise similar in appearance to the blue-skinned Andorians. They are highly telepathic, but do not believe in reading other's thoughts without permission.
Jhamel agrees to help Archer and Shran to save her brother Gareb. Jhamel convinces Gareb to stop the attack, but Valdore kills Gareb.

"Affliction"

Episode Number

91

Phlox is kidnapped by the Klingons

Production Number

091

Season

4

Stardate

27-Nov-2154

Original Airdate

2/18/2005

Story

Manny Coto

Teleplay

Michael Sussman

Director

Michael Grossman

Synopsis

While Enterprise visits Earth for the launch of Columbia, Dr. Phlox is kidnapped by a band of Klingons who are desperate to find a cure for a genetically-engineered virus that threatens their entire race. Meanwhile, Trip begins his new assignment aboard the Starship Columbia as it prepares to embark on its maiden voyage and Reed's ties to a mysterious intelligence organization compromises his allegiance to Archer and Enterprise. Later, T'Pol attempts her first mind-meld in the search for clues to Phlox's whereabouts.

Part 1 of 2.
The virus was created by the Klingons using DNA from the Human Augments in trying to create a Klingon Augment. One of the test subjects had the Livodian flu and the virus mutated. They tried to get Dr. Arik Soong, but were unable, so they took Phlox instead.
Archer walks T'Pol through her mind meld with Hoshi.
After Reed is caught in a lie and erases the Rigellian black box, Archer relieves him from duty and throws him in the brig pending court-martial.
Admiral Gardner has replaced Admiral Forrest as the commander of the fleet.
Kelby has replaced Tucker as the Enterprise Chief Engineer.
Hernandez has to remind Tucker to replace the Enterprise patch on his arm with a Columbia patch.
Hernandez served on the Republic under Captain Jennings before she received command of the Columbia.

"Divergence"

Episode Number

92

Dr. Antaak is left disfigured by the virus

Production Number

092

Season

4

Stardate

Original Airdate

2/25/2005

Story

Teleplay

Judith Reeves-Stevens & Garfield Reeves-Stevens

Director

David Barrett

Synopsis

With the help of Captain Hernandez, Trip and the newly-launched starship Columbia, Archer pursues the kidnapped Phlox deep into Klingon territory, as Phlox decides to cooperate with finding a cure to a virus ravaging a Klingon outpost. Meanwhile, Archer demands that Reed disclose his secret orders when his ties to a mysterious intelligence organization are revealed. Later, when Trip temporarily returns to Enterprise, T'Pol tries to broach an uncomfortable subject with him.

Part 2 of 2.
Phlox finds a cure for the virus, but it leaves 7 million Klingons without ridges, a genetic trait they will pass onto their children. Phlox notes that the appearance can be corrected with cosmetic surgery.
The Columbia's registry is NX-02. It is a slightly different color than Enterprise (more silver-grey) and has minor improvements over Enterprise.

"Bound"

Episode Number

93

The Orion women dance for Archer

Production Number

093

Season

4

Stardate

27-Dec-2154

Original Airdate

4/15/2005

Story

Teleplay

Manny Coto

Director

Allan Kroeker

Synopsis

After Archer forges a deal with the Orions, the trader presents the captain with a gift -- three alluring Orion women who proceed to seduce all the men on board except, mysteriously, Trip.

We learn that Orion women are the ones who are in control -- the men are slaves to their bidding.
The Orion women emit a pheromone which affects the entire crew, except for T'Pol, whose Vulcan physiology is immune. The pheromone causes headaches in the women and it causes Phlox to become tired. T'Pol's mating bond with Trip renders him immune as well.
T'Pol finally admits her feelings for Trip, who tells her that he already asked Captain Hernandez for a transfer back to Enterprise.
Kelby had problems getting along with Trip early on because he feels that Trip's presence on Enterprise threatened his promotion. Apparently he was right because Trip does indeed call Kelby "Lieutenant" instead of "Commander" and then later reveals that he requested a transfer back to Enterprise.

"In a Mirror, Darkly"

Episode Number

94

The U.S.S. Defiant NCC-1764

Production Number

094

Season

4

Stardate

13-Jan-2155

Original Airdate

4/22/2005

Story

Teleplay

Michael Sussman

Director

James L. Conway

Synopsis

In an alternate universe, an amoral, imperialistic version of the Enterprise crew, led by Captain Forrest with Archer as his treacherous first officer, makes an astonishing discovery during a mission into enemy alien territory. Meanwhile, a power-hungry Archer schemes against Captain Forrest, his lover Hoshi, and loyal slave T'Pol, so he can lay full claim to the discovery. Later, Phlox happily tortures a captured Tholian for information requested by Archer.

The episode opened with the first contact scene from the end of Star Trek: First Contact. When Zefram Cochrane is supposed to shake the Vulcan captain's hand, he shoots him instead!
The opening credits featured an instrumental theme song with images of battles instead of exploration.
The Original Series 3rd season episode "The Tholian Web" introduced the Tholians and the Defiant.
The mirror Tholians created a rift in the universe and lured a ship into the mirror universe -- the U.S.S. Defiant NCC-1764, Constitution-class. The ship is approximately 100 years from the future.
The name on the hull is I.S.S. Enterprise. The NX-01 registry is gone, replaced by a mirror universe symbol. There are also yellow stripes painted on the top sides of the saucer section.
Mirror Porthos is a rottweiler instead of a cute beagle.
This episode is the 700th episode of Star Trek produced. (This does not include The Animated Series nor the motion pictures.)
Unlike the other "mirror universe" episodes, this episode (and it's conclusion) are entirely contained within the mirror universe. There is no crossing-over (other than the starship Defiant).

"In a Mirror, Darkly, Part II"

Episode Number

95

Archer takes control of the fleet

Production Number

095

Season

4

Stardate

18-Jan-2155

Original Airdate

4/29/2005

Story

Manny Coto

Teleplay

Michael Sussman

Director

Marvin V. Rush

Synopsis

After using the Defiant to repel a Tholian attack, the power-hungry Archer and Enterprise crew set about using this advanced ship to seize control of all of Earth's Terran Empire. As Archer takes full command of the Defiant and reviews the alternate history of Starfleet, his duplicitous lover Hoshi, a traitorous T'Pol and a reptilian Gorn stowaway hatch schemes of their own.

The crew that arrived on the Defiant in Part 1 wear the TOS uniforms in this episode (since they arrived in EV suits).
The Defiant finds rebel Andorian, Vulcan, and Tellarite ships attacking the I.S.S. Avenger, an NX-class starship commanded by Admiral Black. Soval (sporting a goatee) was the science officer on the Avenger. Archer destroyed the rebels, allowing one to escape as a warning.
Ensign Kelby was killed by the Gorn. Reed put on the TOS red shirt uniform and was also critically injured by the Gorn; he was out of commission for the rest of the episode.
T'Pol notes that "It may take centuries, humanity will pay for its arrogance." See the DS9 episode "Crossover".
After the destruction of the Avenger, Hoshi poisons Archer, takes over the Defiant and declares herself Empress Sato, ordering Fleet Admiral Gardner to surrender.

"Demons"

Episode Number

96

The crew attends the Coalition conference

Production Number

096

Season

4

Stardate

19-Jan-2155

Original Airdate

5/6/2005

Story

Teleplay

Manny Coto

Director

LeVar Burton

Synopsis

On Earth for a historic Starfleet conference to ratify the Coalition of Planets, Archer and the crew uncover a plot by a radical xenophobic group of humans called Terra Prime, led by Paxton, who want to put an end to the increasing number and influence of aliens on Earth. Meanwhile, although T'Pol contends she has never been pregnant, she and Trip learn that Terra Prime has information about their child. Later, a female reporter from Travis' past pursues him for a story.

Part 1 of 2.
Harry Groener previously appeared as Tam Elbrun in the TNG episode "Tin Man".
Colonel Green, seen in video footage here, was originally introduced in the Original Series episode "The Savage Curtain".

"Terra Prime"

Episode Number

97

T'Pol and Tucker grieve for their baby

Production Number

097

Season

4

Stardate

Original Airdate

5/13/2005

Story

Judith Reeves-Stevens & Garfield Reeves-Stevens and André Bormanis

Teleplay

Judith Reeves-Stevens & Garfield Reeves-Stevens and Manny Coto

Director

Marvin V. Rush

Synopsis

In the first steps towards the foundation of the Federation, Captain Archer and the crew must stop Paxton, a well-armed, radical human isolationist leader, who is threatening to destroy Starfleet Command unless all aliens leave Earth immediately.

Part 2 of 2. May 13, 2005 - 8:00 PM, followed by Series Finale at 9:00 PM.
Mayweather finds that his former girlfriend Gannet Brooks works for Starfleet Intelligence.
T'Pol and Tucker's baby girl, named Elizabeth after Tucker's sister, was created from DNA stolen from Enterprise by Ensign Masaro. The baby died shortly after due to faulty cloning by Dr. Mercer.

"These Are The Voyages..."

Episode Number

98

Archer prepares to give his speech

Production Number

098

Season

4

Stardate

47457.1

Original Airdate

5/13/2005

Story

Teleplay

Rick Berman & Brannon Braga

Director

Allan Kroeker

Synopsis

Six years in the future, an emotional Captain Archer and the crew return to Earth to face the decommissioning of Enterprise and signing of the Federation charter, ratifying the newly-formed alliance of planets they helped forge.

Series Finale.
This episode is a holographic simulation run by Riker during The Pegasus mission aboard the U.S.S. Enterprise NCC-1701-D. It contains many references to previous Star Trek people and events. 71 people died on the Pegasus.
Brent Spiner provides his voice as Data in a communication to Troi.
Shran married Jhamel and they had a daughter, Talla. Jhamel is an Aenar (from "The Aenar").
The episode ends with a nice montage of Picard, Kirk and then Archer reciting the "Space, the final frontier..." monologue.
Allan Kroeker also directed the DS9 finale "What You Leave Behind" and the Voyager finale "Endgame".
Jonathan Frakes has appeared in all four Star Trek series since The Next Generation; as Will Riker in this episode and in Voyager's "Death Wish", and as Tom Riker in DS9's "Defiant". Marina Sirtis never appeared on DS9, but did appear in 3 episodes of Voyager as Troi.
Rick Berman and Brannon Braga originally wrote this episode for the Season 3 finale when it looked like Paramount wasn't going to renew the show for a 4th season.
Unlike the series finales for the other Trek spin-offs, this episode is only 1 hour long.